Etching mask, method of making same, etching method, magnetic head device and method of manufacturing same

Abstract

An etching mask is made of a metal such as Permalloy (NiFe) and has a T-shaped cross section made up of a vertical bar having width W 1 and a lateral bar having width W 2 . Through ion beam etching with the etching mask, the region in the surface of a workpiece not covered with the mask is selectively removed by the ion beams applied thereto. In the mask the vertical bar has a region obstructed by the lateral bar and a redeposit portion. As a result, the region of the vertical bar near the interface between the workpiece and the vertical bar that substantially determines the pattern width does not change in width. Consequently, a pattern of the workpiece on which etching has been performed has the top width and bottom width substantially equal to width W 1 of the vertical bar of the mask. The pattern is rectangular in cross section.

What is claimed is:  
     
       1. A method of making an etching mask made of a metal and having a T-shaped cross section including a vertical bar and a lateral bar, including the steps of: 
       forming a film for mask formation on a workpiece and forming an  
       opening in the film for mask formation, the opening reaching the workpiece and having a specific width; and  
       forming a metal film in the opening and over a region around the opening to form the etching mask and removing the film for mask formation, the mask having a T-shaped cross section including a vertical bar and a lateral bar.  
     
     
       2. A method according to claim  1  wherein the thickness of the film for mask formation is made equal to the height of the vertical bar of the mask and the width of the opening is made equal to the width of the vertical bar. 
     
     
       3. A method of making an etching mask made of a metal and having a T-shaped cross section including a vertical bar and a lateral bar, including the steps of: 
       forming a film for mask formation having a specific thickness on a workpiece and performing a first exposure on a region of a specific width in the film by such an exposure amount that reaches the workpiece;  
       after the first exposure, forming a T-shaped exposed region by performing a second exposure on a region in the film having a width greater than that of the region exposed through the first exposure by an exposure amount smaller than that of the first exposure;  
       selectively removing the exposed regions of the film for mask formation to form a T-shaped opening; and  
       forming a metal film in the opening of the film for mask formation to form the etching mask and removing the film for mask formation, the mask having a T-shaped cross section including a vertical bar and a lateral bar.  
     
     
       4. A method according to claim  3  wherein the thickness of the film for mask formation is made equal to the height of the mask, the width of the opening of the film for mask formation formed by the first exposure is made equal to the width of the vertical bar, and the width of the opening formed by the second exposure is made equal to the width of the lateral bar. 
     
     
       5. A method of making an etching mask made of a metal and having a T-shaped cross section including a vertical bar and a lateral bar, including the steps of 
       forming a first film for mask formation on a workpiece and forming a first opening having a specific width that reaches the workpiece in the first film;  
       forming a metal film in the first opening and removing the first film;  
       forming a second film for mask formation on the metal film and the workpiece and then forming a second opening in the second film, the second opening reaching the metal film and having a width greater than that of the metal film; and  
       forming a metal film in the second opening to form the etching mask that is T-shaped in cross section and includes a vertical bar and a lateral bar, and then removing the second film.  
     
     
       6. A method of making an etching mask made of a metal and having a T-shaped cross section including a vertical bar and a lateral bar, including the steps of 
       forming a first film for mask formation on a workpiece and forming a first opening having a specific width that reaches the workpiece in the first film;  
       forming a metal film in the first opening, forming a second film for mask formation on the metal film and the first film, and then forming a second opening in the second film, the second opening reaching the metal film and having a width greater than that of the metal film; and  
       forming a metal film in the second opening to form the etching mask that is T-shaped in cross section and includes a vertical bar and a lateral bar, and then removing the first and second films.  
     
     
       7. A method according to claim  5  wherein the thickness of the first film is made equal to the height of the vertical bar of the mask, the width of the first opening is made equal to the width of the vertical bar, and the width of the second opening is made equal to the width of the lateral bar. 
     
     
       8. A method according to claim  1  wherein the metal film is formed by plating. 
     
     
       9. A method according to claim  8  wherein the plating is electroless plating. 
     
     
       10. An etching method including the steps of: forming an etching mask made of a metal and having a T-shaped cross section on a workpiece, and then performing micromachining of the workpiece by dry etching through the use of the etching mask. 
     
     
       11. An etching method according to claim  10  wherein the dry etching is performed through ion beam etching. 
     
     
       12. A method of manufacturing a magnetic head device comprising an inductive writing head including a first writing pole, a second writing pole corresponding to the first writing pole, and a gap layer placed between the first and second writing poles, including the steps of: 
       stacking a layer to be the first writing pole, the gap layer, and a layer to be the second writing pole in this order and then forming an etching mask made of a metal and having a T-shaped cross section on the layer to be the second writing pole; and  
       selectively removing the layer to be the second writing pole by dry etching using the etching mask to form a rectangular cross section.  
     
     
       13. A method of manufacturing a magnetic head device comprising an inductive writing head including a first writing pole, a second writing pole corresponding to the first writing pole, and a gap layer placed between the first and second writing poles, including the steps of: 
       stacking a layer to be the first writing pole, the gap layer, and a layer to be the second writing pole in this order and then forming an etching mask made of a metal and having a T-shaped cross section on the layer to be the second writing pole; and  
       selectively removing the layer to be the second writing pole, the gap layer, and a region to the middle in depth of the layer to be the first writing pole in this order by dry etching using the etching mask to form a rectangular cross section.  
     
     
       14. A method of manufacturing a magnetic head device comprising an inductive writing head including a first writing pole, a second writing pole corresponding to the first writing pole, and a gap layer placed between the first and second writing poles, including the steps of: 
       stacking a layer to be the first writing pole and the gap layer, and then forming an etching mask made of a magnetic material and having a T-shaped cross section to be the second writing pole on the gap layer; and  
       selectively removing the gap layer and a region to the middle in depth of the layer to be the first writing pole in this order by dry etching using the etching mask to form a rectangular cross section.  
     
     
       15. A method of manufacturing a magnetic head device comprising an inductive writing head including a first writing pole, a second writing pole corresponding to the first writing pole, and a gap layer between the first writing pole and the second writing pole, the method comprising the steps of: 
       stacking a layer to be the first writing pole, the gap layer and a layer to be the second writing pole in this order and then forming an etching mask by the method of claim  5  on the layer to be the second writing pole; and  
       selectively removing the layer to be the second writing pole by dry etching using the etching mask to form a rectangular cross section.  
     
     
       16. A method of manufacturing a magnetic head device comprising an inductive writing head including a first writing pole, a second writing pole corresponding to the first writing pole, and a gap layer between the first writing pole and the second writing pole, the method comprising the steps of: 
       stacking a layer to be the first writing pole, the gap layer and a layer to be the second writing pole in this order and then forming an etching mask by the method of claim  7  on the layer to be the second writing pole; and  
       selectively removing the layer to be the second writing pole by dry etching using the etching mask to form a rectangular cross section.  
     
     
       17. A method of manufacturing a magnetic head device comprising an inductive writing head including a first writing pole, a second writing pole corresponding to the first writing pole, and a gap layer between the first writing pole and the second writing pole, the method comprising the steps of step of: 
       selectively removing the layer to be the second writing pole by dry etching using the etching mask to form a rectangular cross section.  
     
     
       18. A method of manufacturing a magnetic head device comprising an inductive writing head including a first writing pole, a second writing pole corresponding to the first writing pole, and a gap layer between the first writing pole and the second writing pole, the method comprising the steps of: 
       stacking a layer to be the first writing pole, the gap layer and a layer to be the second writing pole in this order and then forming an etching mask by the method of claim  10  on the layer to be the second writing pole; and  
       selectively removing the layer to be the second writing pole by dry etching using the etching mask to form a rectangular cross section.